rwarwahbdjhxbwajhd rwarwahbdjhxbwajhd
  • 24-09-2020
  • Mathematics
contestada

Given that the 3rd term in an arithmetic sequence is -2 and the 7th term is -10, tell me what the 1st term in the sequence is. Explain how you know.

Respuesta :

MathPhys
MathPhys MathPhys
  • 24-09-2020

Answer:

2

Step-by-step explanation:

a₃ = -2

a₇ = -10

The nth term of an arithmetic sequence is:

a = a₁ + d (n − 1)

Therefore:

-2 = a₁ + d (3 − 1) = a₁ + 2d

-10 = a₁ + d (7 − 1) = a₁ + 6d

Subtract the equations:

8 = -4d

d = -2

Plug into either equation to find the first term.

-2 = a₁ + 2(-2)

a₁ = 2

Answer Link

Otras preguntas

Critics of the Articles of Confederation argued that it?
does a tsunami destroy everything
The ability to obtain a driver's license and drive a car is a ___________
“She Walks in Beauty” by Lord Byron Which excerpt best reflects Byron’s appreciation of beauty? Which excerpt best reflects Byron’s appreciation of beauty? “One
In fermentation, which step of cellular respiration is being accomplished?
Which of the following is not a major ocean on Earth? a. Pacific b. Indian c. Atlantic d. Southern
Calculate the number of moles CuCl2 necessary to make 50 mL of a 0.15M solution
A store has 255 wool ponchos to sell. There are 112 adult-sized ponchos that sell for $45 each. The rest are kid-sized and sell for $32 each. If the store sells
Homer's Iliad and Odyssey were examples of what kind of poems?
Before the Revolutionary War, most American colonists called themselves _____. A. "Americans" B. "Frenchmen" C. "Englishmen" D. "Bad, Bad Leroy Brown"